Papers by Keyword: In Vitro

Abstract: The objective of this study was to investigate the in vitro and in vivo biological responses to carbonate apatite (cHA) in comparison to hydroxyapatite (HA). Spheres (400<ø>500 μm) of both materials were synthesized under 5°C (cHA) and 90°C (HA) and not sintered. The in vitro cytocompatibility was determined by the XTT assay, according to ISO 10993-5:2009, after exposure of MC3T3-E1 cells to the materials extracts. Ethics Commission on Teaching and Research in Animals approved this project (CEPA/NAL 193/10) and, subsequently, the biomaterials were grafted in the subcutaneous tissues of mice (n=15). After 1 and 3 weeks, five animals of each group were killed for samples removal containing biomaterials and surrounding tissues for histological examination. Semi-serial (5-μm thick) sections were cut and stained with Hematoxylin and Eosin (HE) and the presence of inflammatory infiltrates and biomaterials resorption were evaluated. The experimental group of 3 weeks didn’t show the presence of spheres of both biomaterials and few spheres were observed after 1 week. Histological analysis showed the granulation tissue around the biomaterials with the presence of multinucleated giant cells. After 3 weeks it was observed the presence of fibrous tissue around biomaterials and few inflammatory cells. No signals of tissue necrosis were observed in both groups in all experimental studied periods. Nanostructured carbonate apatite spheres are cytocompatible, biocompatible and present initial biosorption on the subcutaneous comparable to stoichiometric HA, indicating its suitability for further studies on regenerative medicine.

Abstract: This study investigated the osteoinductive potential of granules of stoichiometric hydroxyapatite (HA) and 0.5% zinc containing hydroxyapatite (ZnHA) in intramuscular (IM) site of rabbit’s abdomen. The biomaterials were both used in granular form, with 75% porosity and particle diameter between 450 and 500μm, sintered at 1100°C. Both materials performed adequately on a multiparametric in vitro cytocompatibility assay, indicating their suitability for in vivo testing. After approval by the Ethics Commission on Teaching and Research in Animals, fifteen rabbits were submitted to general anesthesia, incision and tissue dilatation, and a small site was created for HA (right incision) and ZnHA (left incision) intramuscular implantation. The animals were killed after 2, 4 and 12 weeks for biomaterials and surrounding tissues removal. Histological analysis after 2 weeks revealed the presence of granulation tissue surrounding biomaterials with multinucleated giant cells and no newly formed bone for both materials. After 4 weeks there was fibrous tissue involving the material and few inflammatory cells. Following 12 weeks it was observed the presence of connective tissue surrounding the biomaterial, cellularized enough for the two experimental groups, but it was not observed the presence of bone matrix associated with the biomaterials. We conclude that both biomaterials are cytocompatible and did not present the property of osseoinduction after 12 weeks of implantation.

Abstract: Basic drawbacks of calcium phosphate cements (CPCs) are the brittleness and low strength behavior which prohibit their use in many stress-bearing locations, unsupported defects, or reconstruction of thin bones. Recently, to solve these problems, researchers investigated the incorporation of fibers into CPCs to improve their strength. In the present study, various amounts of a highly bioactive glass fiber were incorporated into calcium phosphate bone cement. The obtained results showed that the compressive strength of the set cements without any fibers optimally increased by further addition of the fiber phase. Also, both the work-of-fracture and elastic modulus of the cement were considerably increased after applying the fibers in the cement composition. Herein, with the aim of using the reinforced-CPC as appropriate bone filler, the prepared sample was evaluated in vitro using simulated body fluid (SBF) and osteoblast cells. The samples showed significant enhancement in bioactivity within few days of immersion in SBF solution. Also, in vitro experiments with osteoblast cells indicated an appropriate penetration of the cells, and also the continuous increase in cell aggregation on the samples during the incubation time demonstrated the ability of the reinforced-CPC to support cell growth. Therefore, we concluded that this filler and strong reinforced-CPC may be beneficial to be used as bone fillers in surgical sites that are not freely accessible by open surgery or when using minimally invasive techniques.

Abstract: Hydroxyapatite/collagen (HAp/Col) nanocomposites with bone-like self-organized nanostructure show excellent bioactivity in vivo. However, they show quite high absorbability for cationic ions and lower culture medium ionic concentrations which adversely affects bone cell proliferation and osteogenic differentiation in in vitro cell culture condition. To address this limitation, in this study we have supplemented Ca²⁺ and Mg²⁺ ions to the HAp/Col nanocomposite membrane sample prior to cell culture to improve it’s in vitro biological properties. The HAp/Col nanocomposite membrane samples were fabricated by the simultaneous titration method using Ca(OH)₂, type-I atelocollagen and H₃PO₄ as starting precursor materials. Prior to in vitro cell culture experiments, the HAp/Col samples were pretreated with Ca²⁺ and/or Mg²⁺ ions by immersing in 10 ml of 20 mM CaCl₂ solution, 20 mM MgCl₂ solution, or a solution containing 20 mM CaCl₂ and 20 mM MgCl₂ for 7 days. In vitro bone cell-material interactions on the pretreated and untreated HAp/Col samples were studied by culturing MC3T3-E1 cells up to 7 days. Enhanced bone cell proliferation was found on all the pretreated HAp/col samples as confirmed by the CCK-8 assay. Interestingly, the HAp/Col samples pretreated with both Ca²⁺ and Mg²⁺ ions showed the maximum viable bone cell density.

Abstract: This paper reports on a water-soluble acid polysaccharide (AAP) and in how it was extracted from Auricularia auricular, acquired by CTAB, and prepared it’s carboxymethylation. Chemical characterization by high-performance liquid chromatography/gel permeation chromatograph (HPLC/GPC), Fourier transform infrared (FT-IR) spectrometer and gas chromatography–mass spectrophotometer (GC–MS) were investigated. Chemical analysis indicated that C AAAP was composed of arabinose, xylose, mannose, glucose and galactose, with the molar ratio at 0.04: 0.13: 1.00: 0.59: 0.29. Moreover, radiation protection against UVB in vitro indicated that at the dose range of 200–500 μg/mL, C AAAP enhanced the protection of HepG2 cells against UVB cytotoxicity than AAAP. However, but at the dose range of 50–150 μg/mL the result was just opposite.

Abstract: To study the effect of different sucrose concentration on bulblet formation, three kinds of Lilium plantlets, Lilium davidii var. unicolor, L. longiflorum ‘White Heaven’ and L. OT ‘Yelloween’ were inoculated on media containing different sugar concentration. It was found that L. davidii var. unicolo had 100% percent in bulblet formation at the sucrose concentration 100g/L, while the diameter and weight increment of bulblets came to the maximum. Both ‘White Heaven’ and ‘Yelloween’ had 100% percent of bulblets formation on the sucrose concentration at 80g/L and 100 g/L. But the diameter and weight increment of bulblets in different varieties had different results. The maximum of ‘White Heaven’ bulblets could be obtained at sucrose concentration 60g/L, while ‘Yelloween’ at 80g/L. It was concluded that sucrose concentrations at 40~80g/L had a positive impact on these 3 lilies bulblets formation in vitro cultures.

Abstract: In this paper, Poly(lactide-co-glycolide) (PGLA) fibers were treated with the plasma. The surface, tensile strength, and contact angle with water of the PGLA fiber were investigated. The results showed that the PGLA fiber after treatment possessed more rough surface and smaller contact angle with water compared with the untreated fiber, but the tensile strength of fiber after treatment was not significantly diffrent form the fiber before treatment. In addition, both the treated and untreated PGA fibers were placed in phosphate buffer solution (PBS) (pH=7.4) at 37 °C up to 2.5 weeks to investigate the effect of plasma treatment on the degradation in vitro. Changes in tensile strength during degradation was investigated. The results showed that the treated PGLA fiber degraded faster compared with the untreated fiber.

Abstract: Tetrandrine can inhibit the proliferation and collagen synthesis of fibroblasts in lung and liver tissue confirmed by a series of clinical research. In this chapter, we investigated the effect of Tetrandrine on the proliferation of human dermal fibroblasts derived from hypertrophic scars. The dermal fibroblasts were isolated from human hypertrophic scar tissues and cultured in vitro. Tetrandrine with different concentration were added to culture medium respectively. The proliferative activities were determined. The result show that when the concentration of added Tetrandrine increased from 5μg/ml to 80μg/ml, the proliferative activities of cultured dermal fibroblasts were decreased gradually in dose-dependent manner. It conclusions that Tetrandrine can obviously inhibit the proliferation of human dermal fibroblasts derived from hypertrophic scars.

Abstract: Human induced pluripotent stem cells is promising for regenerative medicine and tissue engineering. In this chapter, we focus on the culture and characteristics of human induced pluripotent stem cells. The induced pluripotent stem cells were plated on murine embryonic fibroblast feeder cells and expanded in human embryonic stem cells media contained basic fibroblast growth factor. The cells were passaged by collagenase IV digestion method and observed under invert microscope. The expression of alkaline phosphatase was detected by immunocytochemistry. The cultured induced pluripotent stem cells grew well and stability with similar characteristics of human embryonic stem cells. These cells also expressed alkaline phosphatase. They formed embryoid body in feeder-free and suspension culture conditions. The results provide an experimental basis for improvement of induction study and further application to generate patient-specific induced pluripotent stem cells.

Abstract: The effect of poly(L-lactide-co-glycolide)/bioactive glass (PLGA/BG) on cell attachment, proliferation and differentiation of L929 fibroblastic cells was investigated. The results of in-vitro cytotoxicity test indicated that the cells cultured in extract of PLGA/BG and on the surface of composite showed normal growth and proliferation. The cell proliferation and alkaline phosphatase (ALP) activity of fibroblast were significantly improved after 3 and 7 days of culture on PLGA/BG films in comparison with PLGA films. It can be concluded that the addition of bioactive glass into PLGA stimulates the proliferation and differentiation of fibroblastic cells. Therefore, PLGA/BG composites have a promising biological response as a potential biomaterial in medical field.